A drill chuck has as described in U.S. Pat. Nos. 5,145,192 and 5,145,193 a chuck body centered on and adapted to be rotated about a longitudinal axis and unitarily formed with a plurality of forwardly open angled guides angularly spaced about the axis and an axially forwardly directed shoulder. Respective jaws displaceable along the guides in the chuck body are each formed with a row of teeth and a tightening sleeve rotatably surrounds the body and has an axially rearwardly directed shoulder. An inner ring rotatable on the body about the axis is formed internally with a screwthread meshing with the teeth of the jaws so that rotation of the inner ring in one direction moves the jaws radially together and opposite rotation moves them radially apart. This inner ring bears axially forward on the shoulder of the sleeve and axially backward on the shoulder of the body. Interengaging formations rotationally couple the inner ring to the sleeve and a retaining element axially fixed on the chuck body forward of the inner ring bears axially backward on the sleeve. With the system of this prior invention the chuck body has axially rearward of the interengaging formations a predetermined outside diameter and the sleeve has axially rearward of the interengaging formations a predetermined inside diameter greater than the outside diameter of the body. The ring has a predetermined outside diameter smaller than the inside diameter of the sleeve so that the ring can be fitted axially forward into the sleeve and the sleeve and ring together can be fitted axially backward over the body.
Such a chuck with a one-piece threaded ring is assembled by slipping the ring over the chuck body from the rear. Once in place it bears forwardly on a shoulder of the chuck body and rearwardly, normally via a roller bearing, on a snap ring set in the chuck body. Then the tightening sleeve is attached to th threaded ring, often via a fairly complex mechanical connection. It is critical that the tightening sleeve be able to transmit considerable torque in both directions to the threaded ring. Failure of this connection makes the chuck unusable.